Optical spectroscopy systems commonly used to analyze a light radiation spectrum employ prisms or gratings which cause spatial dispersion of the various wavelengths present in the radiation emitted from the source. Wavelengths very closely spaced (e.g. wavelengths which differ by a few nanometers) are to be distinguished in certain cases, such as for instance in characterization of monochromatic sources with a narrow band (e.g. a LED), in Raman or Brillouin spectroscopy etc. Very complex and hence expensive systems must be used to obtain the resolutions necessary in these applications by spatial dispersion. For instance, a system described in the paper "Micro-Raman Studies of Fluoride Glass Optical Fibers", presented by J. A. Freitas, Jr., P. C. Pureza, I. D. Aggarwal and U. Strom at the 6th International Symposium on Halide Glasses, collects and analyses the radiation scattered by a sample by means of a triple spectrometer. Other similarly expensive systems require objectives with very high focal length, which render the system rather cumbersome.